thumb|right|Shah [[Ismail I (1501-1524) watches his troops defeat the Musha'sha leader Sultan Fayyad. Album-mounted folio of Bijan's history created by Mo'en Mosavver, ]]
The Musha'sha' (also spelled Mosha'sha'; ) were a Shi'i Arab dynasty based in the town of Huwaizah in Khuzestan, ruling from 1435 to 1736. Initially starting out as a tribal confederation, they gradually transformed into a zealous Isma'ili Shi'i dynasty. The independence of the Musha'sha' was put to an end in 1508 by the Safavid shah Ismail I (), who claimed to be the only legitimate Shi'i ruler. Following this, the Musha'sha' remained compliant, typically serving as valis or governors under Persian suzerainty for the following centuries.
History
The Musha'sha' were founded and led by Muhammad ibn Falah, an Iraqi-born theologian who believed himself to be the earthly representative of Ali and the Mahdi. From the middle of the 15th century to the 19th century, they came to dominate much of western Khuzestan in southwestern Iran.
Beginning in 1436, Ibn Falah spread his messianic beliefs amongst the less powerful Arab tribes along the area of the present-day border of Iraq and Iran, gaining converts in an attempt to forge a strong tribal alliance. In 1441, they succeeded in capturing the city of Huwaizah in Khuzestan, and during the following ten years the Musha‘sha’iyyah increased their strength and consolidated their power in the area around the city and the Tigris. These early military ambitions were fueled by Muhammad ibn Falah's zealous millenarian theology, which continued to significantly influence the later military campaigns of the Musha‘sha’iyyah decades after his death.
Successors of Ibn Falah were in continual conflict with the Safavid rulers as well as with Arab tribes until overcome by the Safavids in 1508. The conflict with the Safavids was driven not only by politics and territorial domination, but also by theological differences and competition between two rival Shia schools of thought. According to Moojan Momen, both sects adhered to heterodox (ghuluww) Shi'i beliefs.